2023 ACR/EULAR antiphospholipid syndrome classification criteria
Authors: Medha Barbhaiya, Stephane Zuily, Ray Naden, Alison Hendry, Florian Manneville, Mary-Carmen Amigo, Zahir Amoura, Danieli Andrade, Laura Andreoli, Bahar Artim-Esen, Tatsuya Atsumi, Tadej Avcin, Michael H Belmont, Maria Laura Bertolaccini, D Ware Branch, Graziela Carvalheiras, Alessandro Casini, Ricard Cervera, Hannah Cohen, Nathalie Costedoat-Chalumeau, Mark Crowther, Guilherme de Jesús, Aurelien Delluc, Sheetal Desai, Maria De Sancho, Katrien M Devreese, Reyhan Diz-Kucukkaya, Ali Duarte-García, Camille Frances, David Garcia, Jean-Christophe Gris, Natasha Jordan, Rebecca K Leaf, Nina Kello, Jason S Knight, Carl Laskin, Alfred I Lee, Kimberly Legault, Steve R Levine, Roger A Levy, Maarten Limper, Michael D Lockshin, Karoline Mayer-Pickel, Jack Musial, Pier Luigi Meroni, Giovanni Orsolini, Thomas L Ortel, Vittorio Pengo, Michelle Petri, Guillermo Pons-Estel, Jose A Gomez-Puerta, Quentin Raimboug, Robert Roubey, Giovanni Sanna, Surya V Seshan, Savino Sciascia, Maria G Tektonidou, Angela Tincani, Denis Wahl, Rohan Willis, Cécile Yelnik, Catherine Zuily, Francis Guillemin, Karen Costenbader, Doruk Erkan, Nancy Agmon-Levin, Cassyanne Aguilar, Paula Alba, Oral Alpan, Ales Ambrozic, Luis Andrade, Simone Appenzeller, Yackov Berkun, Antonio Cabral, Guillame Canaud, Pojen Chen, Cecilia Chighizola, Rolando Cimaz, Maria Jose Cuadrado, Philip G de Groot, Philippe de Moerloose, Ronald Derksen, Thomas Dörner, Paul Fortin, Bill Giannakopoulos, Emilio B Gonzalez, Murat Inanc, Gili Kenet, Munther Khamashta, Martin Kriegel, Steven Krilis, Danyal Ladha, Patti Massicotte, Gale McCarty, Jamal Mikdashi, Barry Myones, Lisa Sammaritano, Flavio Signorelli, Arzu Soybilgic, Scott Woller, Ray Zuo
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Objective</h3> To develop new antiphospholipid syndrome (APS) classification criteria with high specificity for use in observational studies and trials, jointly supported by the American College of Rheumatology (ACR) and EULAR. <h3>Methods</h3> This international multidisciplinary initiative included four phases: (1) Phase I, criteria generation by surveys and literature review; (2) Phase II, criteria reduction by modified Delphi and nominal group technique exercises; (3) Phase III, criteria definition, further reduction with the guidance of real-world patient scenarios, and weighting via consensus-based multicriteria decision analysis, and threshold identification; and (4) Phase IV, validation using independent adjudicators' consensus as the gold standard. <h3>Results</h3> The 2023 ACR/EULAR APS classification criteria include an entry criterion of at least one positive antiphospholipid antibody (aPL) test within 3 years of identification of an aPL-associated clinical criterion, followed by additive weighted criteria (score range 1–7 points each) clustered into six clinical domains (macrovascular venous thromboembolism, macrovascular arterial thrombosis, microvascular, obstetric, cardiac valve, and hematologic) and two laboratory domains (lupus anticoagulant functional coagulation assays, and solid-phase enzyme-linked immunosorbent assays for IgG/IgM anticardiolipin and/or IgG/IgM anti–β<sub>2</sub>-glycoprotein I antibodies). Patients accumulating at least three points each from the clinical and laboratory domains are classified as having APS. In the validation cohort, the new APS criteria vs the 2006 revised Sapporo classification criteria had a specificity of 99% vs 86%, and a sensitivity of 84% vs 99%. <h3>Conclusion</h3> These new ACR/EULAR APS classification criteria were developed using rigorous methodology with multidisciplinary international input. Hierarchically clustered, weighted, and risk-stratified criteria reflect the current thinking about APS, providing high specificity and a strong foundation for future APS research.